---
title: "Centos单网卡双网关配置"
id: "212"
type: "post"
slug: "centos%e5%8d%95%e7%bd%91%e5%8d%a1%e5%8f%8c%e7%bd%91%e5%85%b3%e9%85%8d%e7%bd%ae"
published_at: "2018-10-29T09:45:19+00:00"
modified_at: "2020-08-30T15:14:21+00:00"
url: "https://www.hitsword.org/2018/212.html"
markdown_url: "https://www.hitsword.org/2018/212.md"
excerpt: "在网关做端口映射的时候遇到这种问题。网关192.168.0.1映射端口22给192.168.0.100时可以， […]"
taxonomy_category:
  - "网关"
taxonomy_post_tag:
  - "Centos"
  - "网关"
---

# Centos单网卡双网关配置

在网关做端口映射的时候遇到这种问题。网关192.168.0.1映射端口22给192.168.0.100时可以，但是同时192.168.0.2映射端口给192.168.0.100就不行，是应为Centos数据包默认走默认网关，而不是原路返回。  
 **网络结构如下：**

```
网卡eth0 IP 192.168.0.100/24 默认网关 192.168.0.1
网卡eth0:0 IP 192.168.0.101/24 专属网关 192.168.0.2
```

  
 vim /etc/sysconfig/network-scripts/ifcfg-eth0  
```
TYPE=Ethernet
BOOTPROTO=none
DEVICE=eth0
ONBOOT=yes
IPADDR=192.168.0.100
PREFIX=24
GATEWAY=192.168.0.1
DNS1=192.168.0.1
DNS2=192.168.0.2
```

  
 vim /etc/sysconfig/network-scripts/ifcfg-eth0:0  
```
TYPE=Ethernet
BOOTPROTO=none
DEVICE=eth0:0
ONBOOT=yes
IPADDR=192.168.0.101
PREFIX=24
```

  
 加一个备用路由表252 backup  
 vim /etc/iproute2/rt_tables  
```
#
# reserved values
#
255     local
254     main
253     default
0       unspec
#
# local
#
#1      inr.ruhep
252     backup
```

  
 路由表规则  
```
ip route flush table backup
ip route add default via 192.168.0.2 dev eth0:0 src 192.168.0.101 table backup
ip rule add from 192.168.0.101 table backup
```

  
**路由表规则静态化【Centos6】**  
 方法1:  
 写到/etc/rc.local  
```
vim /etc/rc.local
ip route flush table backup
ip route add default via 192.168.0.2 dev eth0:0 src 192.168.0.101 table backup
ip rule add from 192.168.0.101 table backup
```

  
 方法2(建议):  
 写到/etc/sysconfig/network-scripts/route-interface和rule-interface  
```
vim /etc/sysconfig/network-scripts/route-eth0:0
default via 192.168.0.2 dev eth0:0 src 192.168.0.101 table backup
vim /etc/sysconfig/network-scripts/rule-eth0:0
from 192.168.0.101 table backup
```

  
**路由表规则静态化【Centos8】**  
```
nmcli connection modify eth0:0 +ipv4.routes "0.0.0.0/0 192.168.0.2 src=192.168.0.101 table=252"
nmcli connection modify eth0:0 +ipv4.routing-rules "priority 32765 from 192.168.0.101 table 252"
```